US2270974A - Centerless grinder - Google Patents

Description

Jan. 27, 1942. A. SCRIVENER CENTERLESS GRINDER Filed June 9, 1941 N EIARTHUR SCRIVENER N INVENTOR V BY M M TTORNEYS Patented Jan. 27, 1942 CENTERLESS GRINDER Anna? serr'v'ener, B's Application June 9", 1941-;lSeriaI. No. 391,202 c In Great Britain Aiiril 8, 1940' mn ihanfnnglana speedmgmpdn theamotnt-ofwork which can b'eproducedin' a given time by 'the'machine with a. minimum or a physical start of the operator; The invention consists of improvements in or 'connected with centeness grinde'rs; wherein means are" provided for effetting a 'power-operated' release of the workpiece upon the co'mple- 'tion or the grinding o eration; saidpower operation'wbeing effected from a; mechanicaior ele'c-s tri'cali or ether ower drive which -is coupled to the release mechanism at: and for the p'eritd of 1 the'releas operationz Y mediately withinbutfree from contact with the Ve'driving-sur'faceofthe pulley! i a length ,or section of. resilient V=belting 5 which is secured to the undersurface of a bar 6 which is'aligned withjl'and linkediby means of the pin 1 to the springs-loaded hammer bar" 3. Normally this hamme'rbar 3 and consequently the bar 6 which is linketi'thereto. are maintained at their posi tionlof rest as seen in Fig I of the drawing,,free 'o'f the' workpiece or of the interposed springloaded member 8, by means of coiled compressionspri'ngs 9 and 9a disposed around the ham:- mer bar '3'within' a slotted framework 10 in which the bar is mounted. within the, bearings 1'06," one end .of each" spring Sand 9a. bearing againsttheframework In and the otherend of "each spring bearingagai-nst the respective abutment's l'l' and He pinned to the'hammer bar 3;

, O'ne means of carrying the present invention into efiectas applied to a centerless grinder of 7 known construction will now be described with reference to the accompanying sheet of drawings. in which: a

Fig. 1 is a part sectional side elevation illustrating the release mechanism.

Fig. 2 is a part sectional fragmentary view illustrating the trigger release mechanism which is associated with the mechanism seen in Fig. 1 through a flexible control.

The release of the workpiece is effected as in accordance with existing'practice by imparting to the workpiece upon completion of the grinding operation and immediately subsequent to or coincident with the freeing movement of the grinding wheels a blow either directly on one end or face of the workpiece or on a member interposed between the hammer and the workpiece which ensures its positive release or discharge from the grinding position. Ordinarily this blow is imparted by means of a springloaded hammer bar which is designed to give a blow through a positive link connection which is entirely under the manual control and operation of the operator, and in the case of heavy work or larger machines might involve a considerable amount of physical energy In the present machine a illustrated by the accompanying drawing the hammer blow or release motion of the hammer bar 3 is imparted by a power drive efiected say by means of a continuously running small electric motor on the spindle of which is mounted a Vpu1ley 4. Located im- Mounted adjacent to the striker'end of the hammerbar 3: and pinned thereto is another; abutmerit l-z-wliich serve'szto contactthe outer end of th slotted framework I0 'andsconstitutesyan inner l mit' s'top for theh'ainme'r bar-16.11 1

" 'lhei section orlengthot V-belting J 5 and. the bar 6 to which it is secured are normally maintained in a slightly raised or free position relative to the peripheral V of the driving pulley 4 by means of a pair of slidably mounted guide wheels I3, 13a. disposed one aboveand the other below the belt-carrying bar 6, the pair of rollers l3, l3'a being mounted in a slide block I4 disposed and vertically movable within one'end of the slotted framework It], the said slide block and guide wheels being capable of initial adjustment or setting within their mounting in the framework by means of an adjusting screw and nut connection [5 having a coiled spring l6 introduced between the undersurface of the ,nut and one face of the framework II]. To the lower end of this slide block Hi there is pivotally connected one end of a flexible cable I! which extends to and is connected at its other end with a pivotally mounted bracket l8 which constitutes part of a trigger mechanism.

The bracket I8 is mounted to pivot about the pin 18a and is provided with an adjustable stop lBb which determines the limit of pivotal motion of a co-operating trigger part l9 which can be moved through an are about its pivot I911 on the bracket I8, the limit of motion of the trigger part I!) relative to the bracket l8 being determined in the one direction by means of the set ting of the adjustable stop [8b mounted on the bracket l8. The trigger l9b which forms part of the trigger part l9 hereinbefore referred to is contacted by the co-operating trigger 20 mounted on the crank 2| which rocks about the spindle 2|a, motion being imparted to the crank 2| through a link rod 22 pivotally connected to the arm of the crank. The link rod is. pivotally connected at its other end to a release lever (not shown) which is operated to release the grinding wheels and free the workpiece in accordance with known practice. The trigger 20 is by this release motion given a motion in the direction of the arrow (Fig. 2) when it will contact with the complementary trigger l9b, rock the part [9 into contact with the adjustable stop I81) and thereby rock the bracket I8 about its pivot 18a to exert a pull on the flexible cable IT. The return of the bracket I8 and trigger part 19 is effected tively engage the peripheral V groove of the driven pulley associated with the electric motor; thus there is imparted to the bar 6 and to the hammer bar 3 pivotally connected thereto a sudden longitudinal motion .to the left in the direction of the workpiece, against the resistance of the pair of coiled compression springs 9 and 9a surrounding the hammer bar 3, thereby causing the free end of the hammer bar to strike the workpiece or a spring-loaded member 8 interposed between the hammer bar and the workpiece and positively release or discharge the workpiece from its now released position within the grinding by the pull of the coil spring I6 "through the slide block M to which the other end of the flexible cable I! is anchored, the crank 2| being returned to its normal position as seen in Fig. 2

of the drawing by the operation of the'irelease lever which is pivotally connected to the link rod 22; a'trip action obtaining between the complementary-triggers 20 and l9b.

' The operation of the mechanism is as follows: When the grinding operation has been completed the release lever of the machine is moved through an are thereby causing the trigger which is associated therewith to contactiwith. the trigger l9b forming part of the trigger part I9 pivotally mounted on the pivotal bracket I8, .to one part of which the flexible cable I! is: anchored as clearly'seen in Fig. 2, whereby a limited arcuate motion is imparted to the bracket I8 aboutv its pivot Isa, thus transmitting a pull to the flexible cable I! whichin turn pulls down the slideiblock l4 together with the pairof rollers l3 l3a 1(the lower one of which l3a serves to normally sup- 7 port in the raised position the slide bar 6 through the V section or length of belting mounted thereon); againstithe :resistance of the coiled compression spring l6 which is associated with the slide block 14. This motion causes the sectionior lengthof V-belting tomomentarily posiwheels, the only effort required by the operator to effect this release being that of causing an engagement between the two triggers hereinbefore referred to, which is a slight, limited operation, the whole of the positive energy required for effecting a blow of the hammer bar being obtained from the power drive of the electric motor. V

It will be appreciated that in place of the electric'motor there may be substituted a continuously rotating pulley driven from any convenient power source which would be coupled to the V-pulley 4.

I.claim: n

A centerless; grinder comprising, in combination, ahammer unit for ejecting the workpiece, biased toward itsinoperative position, a friction surface ,ona portion of the hammer unit, a'constantly rotating friction member normally spaced from said friction surface. said portion of the hammer unit and said rotating friction member being movable relative to one another to bring said friction member and said'friction surface into contact; and the direction of rotation of said friction member being such that upon establishment of such contactqan ejecting move;- ment is imparted to. the hammerunit, and actuating means for bringing said rotating friction member and said frictionsurface into contact.

5 ARTHUR SCRIVENER;

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